protected boolean notifySignalStrength() {
   boolean notified = false;
   synchronized (mCellInfo) {
     if (!mSignalStrength.equals(mLastSignalStrength)) {
       try {
         mPhoneBase.notifySignalStrength();
         notified = true;
       } catch (NullPointerException ex) {
         loge(
             "updateSignalStrength() Phone already destroyed: "
                 + ex
                 + "SignalStrength not notified");
       }
     }
   }
   return notified;
 }